print(7^7)  #0 相同的数异或为0
print(7^0)  #7 任何数与0异或为自身

print('-' * 50)

my_list=[2,2,3,4,5,3,4] #2^2^3^4^5^3^4 = 5
result = 0
for i in my_list:
    result^=i
print(result)

